The majority of roofing failures occur in two areas, at the edge of the roof at an exterior parapet wall and along interior walls that extend above the surface of the roof. The term “roof walls” refers to walls that extend above a roof surface, and includes both interior and exterior walls. If the top of the walls are not protected, water can penetrate the roof system and the interior of the building and cause damage. Therefore, properly protecting roof walls is essential to protecting against water damage.
Coping systems are used to cap and protect walls on building rooftops and to enhance the building's overall appearance. Coping systems typically include a cap that is installed along the top of the walls. The cap improves the appearance of the walls and increases the resistance of the roof walls to wind-driven rain. To withstand winds, systems have been developed to hold the coping cap to the roof wall. In traditional coping systems some of the elements are secured either to one another or the wall or both with fasteners that pass through one or more of the elements and remain exposed to the weather. These fasteners can promote unsightly corrosion and also can provide a pathway for water to pass through the coping system to the building.
One system employs a mounting plate secured to the wall and a cover mounted over it to cover the fasteners that hold the mounting plate to the wall. Both the mounting plate and the cover have U-shape cross-sections, with the ends of the mounting plate turned inwardly. A spring is placed between the cover and the mounting plate. These elements are designed so that the cover covers the mounting plate and the inwardly-turned portions of the cover can extend past the ends of the mounting plate before the spring biases those inwardly-turned portions against the ends of the mounting plate. The system components are thus held together and to a roof wall without requiring any fasteners to pass through the cover, thereby eliminating a potential source of corrosion and a pathway for water to penetrate the system.
It is also important to keep water way from the roof wall at seams between sections of the cover. To protect the seams many coping systems use sealants to seal the joints and keep water out of the system. The sealants must be applied carefully, are messy and time-consuming to use, and can fail over time and thus require periodic maintenance. Another system uses a drain plate under the seam to divert any water that does enter at the seam. Unfortunately, as temperature changes cause the cover to expand and contract, the drain plates can migrate away from the seams they are meant to protect.